Download modular cascaded h-bridge multilevel pv inverter with distributed

MODULAR CASCADED H-BRIDGE MULTILEVEL PV
INVERTER WITH DISTRIBUTED MPPT FOR GRIDCONNECTED APPLICATIONS
ABSTRACT
This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter
for single- or three-phase grid-connected applications. The modular cascaded multilevel
topology helps to improve the efficiency and flexibility of PV systems. To realize better
utilization of PV modules and maximize the solar energy extraction, a distributed maximum
power point tracking control scheme is applied to both single- and three-phase multilevel
inverters, which allows independent control of each dc-link voltage. For three-phase gridconnected applications, PV mismatches may introduce unbalanced supplied power, leading to
unbalanced grid current.
To solve this issue, a control scheme with modulation compensation is also proposed. An
experimental three-phase seven-level cascaded H-bridge inverter has been built utilizing nine Hbridge modules (three modules per phase). Each H-bridge module is connected to a 185-W solar
panel. Simulation and experimental results are presented to verify the feasibility of the proposed
approach.